I am the younger son in the family, and I have an older brother who is moving out?

Yes, they will get over it. My parents cried when each one of us, their six older kids moved out. They asked us to stay with them through college. But we wanted our independence. We always visited, though. I'm sure your brother will, too.. We're all adults (except for my 16 year old sister), some of us married with kids, and still have family Sunday brunch :-)